A sauna is a small room or house designed as a place to experience dry or wet heat sessions, or an establishment with one or more of these and auxiliary facilities.
A sauna session can be a social affair in which the participants disrobe and sit or recline in temperatures typically between 70 °C (158 °F)and 100 °C (212 °F). This induces relaxation and promotes sweating.
Saunas can be divided into two basic styles: conventional saunas that warm the air or infrared saunas that warm objects. Infrared saunas may use various materials in their heating area such as charcoal, active carbon fibers, and other materials.
Use
A steam sauna can take 30 minutes to heat up when first started. Some users prefer taking a warm shower beforehand to speed up perspiration in the sauna. When in the sauna users often sit on a towel for hygiene and put a towel over the head if the face feels too hot but the body feels comfortable. In Russia, a felt "banya hat" may be worn to shield the head from the heat; this allows the wearer to increase the heat on the rest of the body.
Most adjustment of temperature in a sauna comes from,
- amount of water thrown on the heater, this increases humidity, so that sauna bathers perspire more copiously.
- length of stay in the sauna
- positioning when in the sauna
It is cooler on the lower benches, and away from the heater elements, as the heat rises it will be hotter higher up. Provided the sauna is not crowded, lying on a bench is considered preferable as it gives more even temperature over the body. Users increase duration and the heat gradually over time as they adapt to sauna.
When pouring water onto the heater, it will cool down the heater, but carry more heat into the air via advection, making the sauna warmer.
Perspiration is a sign of autonomic responses trying to cool the body. Users are advised to leave the sauna if the heat becomes unbearable, or if they feel faint or ill. Some saunas have a thermostat to adjust temperature, but management and other users expect to be consulted before changes are made. The sauna heater and rocks are very hot - one must stay well clear to avoid injury, particularly when water is poured on the sauna rocks, which creates an immediate blast of steam. Combustibles on or near the heater have been known to result in fire. Wet floors can be slippery. Contact lenses dry out in the heat. Jewellery or anything metallic, including glasses, will get hot in the sauna and can cause discomfort or burning.
Temperature on different parts of the body can be adjusted by shielding from the steam radiator with a towel. Shielding the face with a towel has been found to reduce the perception of heat. It is advised, especially for women to put an additional towel or special cap on hair to avoid their dryness. Few people can sit directly in front of the heater without feeling too hot from radiant heat, but their overall body temperature may be insufficient. As the person’s body is often the coolest object in a sauna room, steam will condense into water on the skin; this can be confused with perspiration.
In an infrared dry sauna, the heaters produce infrared rays that penetrate the skin layers and heat more deeply, It is the user that heats up not so much the room, so it will be cooler. For safety reasons water is not placed on these types of heaters.
Cooling down is part of the sauna cycle and is as important as the heating. Among users it is considered good practice to take a few moments after exiting a sauna before entering a cold plunge, and to enter a plunge pool by stepping into it gradually, rather than immediately immersing fully. Until used to having a full cold shower, warm ones are used gradually make it colder so that the shock is not so great. After a shower, feeling cold or shivering indicates it is enough, the shiver is a sign of the autonomic responses, trying to warm the body. This is considered a signal for the sauna again. If however illness is felt later or during that day, a less hot sauna and warmer, longer cool down is tried then the next day. In summer, any after effects like headache or nausea can come from insufficient cool down after the sauna, or from dehydration, failure to drink enough fluids. Sleep disturbances can also occur if not cooled down properly, even though not feeling hot, the heat in the core of the body may disrupt sleep as the body tries to cool at night. In summer, a session is often started with a cold shower.
Therapeutic sauna has been shown to aid adaptation, reduce stress hormones, lower blood pressure and improve cardiovascular conditions.
Health risk and Benefit
Saunas can be dangerous due to the risk of heat prostration or the even more serious hyperthermia. Children and older persons who have heart disease or seizure disorders or those who use alcohol or cocaine are especially vulnerable.
Prolonged stay in a sauna may lead to the loss of electrolytes from the body, the same as after rigorous exercise. Risks of dehydration leading to heat stroke in more sensitive individuals can occur and may be reduced by regular sipping of water or isotonic drinks, but not alcohol, during the sauna. Sauna bathing and heavy drinking of alcoholic beverages, and also sauna bathing during alcohol withdrawal (hangover) phase can undoubtedly create real health risks.
Many of the sauna therapeutic trials used a regular schedule of at least 5 days a week and often daily for one to three months, then several times a week for extended periods.
In some countries the local gymnasium is usually the closest and most convenient and some pool, major sport, or even resort complexes also contain a sauna. Therapeutic Sauna is often carried out in conjunction with physiotherapy or hydrotherapy, gentle exercises within the capability of the person without exacerbating symptoms
Benefits
The beneficial effects of therapeutic sauna are both temporary and long term.
Contraindications to sauna include unstable angina pectoris, recent myocardial infarction, and severe aortic stenosis. Sauna is safe, however, for most people with stable coronary heart disease. It is not harmful to the aged when used in moderation, is safe even for young infants over 3 months if limited to short (< 3 minutes) sessions, and does not affect wound healing. Sauna use may reduce the incidence of the common cold, and temporarily relieve the symptoms. It increases performance in endurance sport, increases plasma volume and red cell volume in athletes, decreased systolic blood pressure, significantly improved exercise tolerance, increased peak respiratory oxygen uptake, and enhanced anaerobic threshold in chronic conditions.
Sauna plus multidisciplinary treatment may reduce chronic pain more effectively than multidisciplinary treatment alone. Sauna reduces chronic pain more effectively than cognitive behaviour therapy. It is indicated for rheumatic pain (with cold shower) but not for neuropathic pain. Is effective for appetite loss and mild depression. Indicated in reducing symptoms in Chronic Fatigue Syndrome, and rheumatoid arthritis, and indicated for anorexia nervosa. Sauna improves function in conditions such as congestive heart failure, and high blood pressure, improves vasodilation, improves heart arrhythmia, and reduces heart rate on exercise. Sauna has been proposed for treatment of other conditions such as glaucoma, Sjogren syndrome, chronic fatigue syndrome, fibromyalgia, anorexia nervosa, obstructive lung disease, recuperation after childbirth, and also for lifestyle related diseases of, diabetes, arteriosclerosis, obesity, hypertension, hyperlipidemia, atherosclerosis and smoking induced symptoms.
With cold exposure
In addition a sauna followed by a cold shower has been shown to reduce pain in rheumatoid arthritis where pain is mediated by sensitised c-fibre sympathetics. Regular saunas have also been found to improve micro circulation reduce vasoconstriction and hypertension. Many symptoms of chronic illnesses may be due to vasoconstriction effects e.g. cold sensitivity, pain even mood states, and sauna improves microcirculation and blood supply to constricted areas.
Research has also shown that adaptation to cold through short term cold stimulus, as in cold swimming, immersion (or showers) has the added benefit of improving the body's anti oxidant capabilities, with increases in glutathione and reduction of uric acid, which may mean better handling of the stresses of illness. Those that are shown to involve reduced glutathione or increased glutathione use, include; cardiovascular conditions, pulmonary diseases, diabetes, inflammatory bowel diseases, cancer, osteoporosis, aging, and after pesticide exposure. Conditions involving oxidative stress include neuro degenerative diseases, CFS, bone fracture and others. Conditions in which increased uric acid may be a risk factor include, gout, metabolic disease and vascular diseases.
A reported study from the Thrombosis Institute in London into the effects of the cold bathing found that volunteers that followed a disciplined daily regime had increased immune white blood cells and the level of the bodies natural blood thinning enzymes substantially increased, improving micro circulation. It also stimulated the production of hormones such as testosterone in men, and boosted women's production of estrogen. Cold water immersion raises thresholds of pain tolerance, and aids adaptation to cold, reduces muscle spasm, can influence the frequency of respiratory infections and improve subjective well-being. It may cause an immunological modulation in terms of the Th1-type pattern, which is a proinflammatory cytokine profile. It is involved in diseases such as arthritis, diabetes, inflammatory myopathies, inflammatory bowel disease, psoriasis, CFS, fibromyalgia, chronic pain, fatigue conditions, auto-immune disease and other inflammatory conditions. Cold water adaptation reduced total cholesterol and LDL cholesterol, lowered plasma viscosity and blood pressure rate product. Cold water immersion reduces recovery time in athletes, enhances repeat performance and reduces exercise induced muscle damage.
Cold water exposure challenges both the neuro-endocrine and the immune systems, reduces stress hormones and attenuates their response. Increases ADH and cortisol and increases immunomodulatory cytokines. Cold water exposure and adaptation can modify the sensory functions of hypothalamic thermoregulatory centres to lower heat loss and produce less heat during cold exposure and have immunostimulating effects. The thermogenic action of adrenaline in cold exposure produces heat and may reduce this stress hormone. An important effect is the ability of sauna to use up excess sympathetic nerve tone in both the central and peripheral nervous systems and just as importantly use up excess levels of local tissue hormones involved in feedback loops to the hypothalamus, thus aiding recovery in chronic illness.
Some basic tips before entering the sauna:
- Don't drink alcohol, as it works as a depressant, where the blood is moving slowly and the nerve endings are literally shutting down, and counteracts the benefits of the sauna.
- Older people need to avoid or limit their time in the sauna.
- People with heart ailments or respiratory diseases need to avoid the sauna, and anyone with chronic ailments needs to check first with his or her doctor.
- Don't eat prior to the sauna.
- Avoid drug use and the sauna — tranquilizers, stimulants, and other prescribed drugs alter the body's metabolism and could produce dour effects in the heat.
- If you experience dizziness, problems with breathing, or a general feeling of ill health, leave the sauna immediately.
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